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Revision 1.206 by root, Tue Oct 28 12:31:38 2008 UTC

10 10
11 // a single header file is required 11 // a single header file is required
12 #include <ev.h> 12 #include <ev.h>
13 13
14 // every watcher type has its own typedef'd struct 14 // every watcher type has its own typedef'd struct
15 // with the name ev_<type> 15 // with the name ev_TYPE
16 ev_io stdin_watcher; 16 ev_io stdin_watcher;
17 ev_timer timeout_watcher; 17 ev_timer timeout_watcher;
18 18
19 // all watcher callbacks have a similar signature 19 // all watcher callbacks have a similar signature
20 // this callback is called when data is readable on stdin 20 // this callback is called when data is readable on stdin
21 static void 21 static void
22 stdin_cb (EV_P_ struct ev_io *w, int revents) 22 stdin_cb (EV_P_ ev_io *w, int revents)
23 { 23 {
24 puts ("stdin ready"); 24 puts ("stdin ready");
25 // for one-shot events, one must manually stop the watcher 25 // for one-shot events, one must manually stop the watcher
26 // with its corresponding stop function. 26 // with its corresponding stop function.
27 ev_io_stop (EV_A_ w); 27 ev_io_stop (EV_A_ w);
30 ev_unloop (EV_A_ EVUNLOOP_ALL); 30 ev_unloop (EV_A_ EVUNLOOP_ALL);
31 } 31 }
32 32
33 // another callback, this time for a time-out 33 // another callback, this time for a time-out
34 static void 34 static void
35 timeout_cb (EV_P_ struct ev_timer *w, int revents) 35 timeout_cb (EV_P_ ev_timer *w, int revents)
36 { 36 {
37 puts ("timeout"); 37 puts ("timeout");
38 // this causes the innermost ev_loop to stop iterating 38 // this causes the innermost ev_loop to stop iterating
39 ev_unloop (EV_A_ EVUNLOOP_ONE); 39 ev_unloop (EV_A_ EVUNLOOP_ONE);
40 } 40 }
41 41
42 int 42 int
43 main (void) 43 main (void)
44 { 44 {
45 // use the default event loop unless you have special needs 45 // use the default event loop unless you have special needs
46 struct ev_loop *loop = ev_default_loop (0); 46 ev_loop *loop = ev_default_loop (0);
47 47
48 // initialise an io watcher, then start it 48 // initialise an io watcher, then start it
49 // this one will watch for stdin to become readable 49 // this one will watch for stdin to become readable
50 ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); 50 ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ);
51 ev_io_start (loop, &stdin_watcher); 51 ev_io_start (loop, &stdin_watcher);
103Libev is very configurable. In this manual the default (and most common) 103Libev is very configurable. In this manual the default (and most common)
104configuration will be described, which supports multiple event loops. For 104configuration will be described, which supports multiple event loops. For
105more info about various configuration options please have a look at 105more info about various configuration options please have a look at
106B<EMBED> section in this manual. If libev was configured without support 106B<EMBED> section in this manual. If libev was configured without support
107for multiple event loops, then all functions taking an initial argument of 107for multiple event loops, then all functions taking an initial argument of
108name C<loop> (which is always of type C<struct ev_loop *>) will not have 108name C<loop> (which is always of type C<ev_loop *>) will not have
109this argument. 109this argument.
110 110
111=head2 TIME REPRESENTATION 111=head2 TIME REPRESENTATION
112 112
113Libev represents time as a single floating point number, representing the 113Libev represents time as a single floating point number, representing the
276 276
277=back 277=back
278 278
279=head1 FUNCTIONS CONTROLLING THE EVENT LOOP 279=head1 FUNCTIONS CONTROLLING THE EVENT LOOP
280 280
281An event loop is described by a C<struct ev_loop *>. The library knows two 281An event loop is described by a C<struct ev_loop *> (the C<struct>
282types of such loops, the I<default> loop, which supports signals and child 282is I<not> optional in this case, as there is also an C<ev_loop>
283events, and dynamically created loops which do not. 283I<function>).
284
285The library knows two types of such loops, the I<default> loop, which
286supports signals and child events, and dynamically created loops which do
287not.
284 288
285=over 4 289=over 4
286 290
287=item struct ev_loop *ev_default_loop (unsigned int flags) 291=item struct ev_loop *ev_default_loop (unsigned int flags)
288 292
380=item C<EVBACKEND_EPOLL> (value 4, Linux) 384=item C<EVBACKEND_EPOLL> (value 4, Linux)
381 385
382For few fds, this backend is a bit little slower than poll and select, 386For few fds, this backend is a bit little slower than poll and select,
383but it scales phenomenally better. While poll and select usually scale 387but it scales phenomenally better. While poll and select usually scale
384like O(total_fds) where n is the total number of fds (or the highest fd), 388like O(total_fds) where n is the total number of fds (or the highest fd),
385epoll scales either O(1) or O(active_fds). The epoll design has a number 389epoll scales either O(1) or O(active_fds).
386of shortcomings, such as silently dropping events in some hard-to-detect 390
387cases and requiring a system call per fd change, no fork support and bad 391The epoll syscalls are the most misdesigned of the more advanced event
388support for dup. 392mechanisms: problems include silently dropping fds, requiring a system
393call per change per fd (and unnecessary guessing of parameters), problems
394with dup and so on. The biggest issue is fork races, however - if a
395program forks then I<both> parent and child process have to recreate the
396epoll set, which can take considerable time (one syscall per fd) and is of
397course hard to detect.
398
399Epoll is also notoriously buggy - embedding epoll fds should work, but
400of course doesn't, and epoll just loves to report events for totally
401I<different> file descriptors (even already closed ones, so one cannot
402even remove them from the set) than registered in the set (especially
403on SMP systems). Libev tries to counter these spurious notifications by
404employing an additional generation counter and comparing that against the
405events to filter out spurious ones.
389 406
390While stopping, setting and starting an I/O watcher in the same iteration 407While stopping, setting and starting an I/O watcher in the same iteration
391will result in some caching, there is still a system call per such incident 408will result in some caching, there is still a system call per such incident
392(because the fd could point to a different file description now), so its 409(because the fd could point to a different file description now), so its
393best to avoid that. Also, C<dup ()>'ed file descriptors might not work 410best to avoid that. Also, C<dup ()>'ed file descriptors might not work
394very well if you register events for both fds. 411very well if you register events for both fds.
395 412
396Please note that epoll sometimes generates spurious notifications, so you
397need to use non-blocking I/O or other means to avoid blocking when no data
398(or space) is available.
399
400Best performance from this backend is achieved by not unregistering all 413Best performance from this backend is achieved by not unregistering all
401watchers for a file descriptor until it has been closed, if possible, 414watchers for a file descriptor until it has been closed, if possible,
402i.e. keep at least one watcher active per fd at all times. Stopping and 415i.e. keep at least one watcher active per fd at all times. Stopping and
403starting a watcher (without re-setting it) also usually doesn't cause 416starting a watcher (without re-setting it) also usually doesn't cause
404extra overhead. 417extra overhead. A fork can both result in spurious notifications as well
418as in libev having to destroy and recreate the epoll object, which can
419take considerable time and thus should be avoided.
405 420
406While nominally embeddable in other event loops, this feature is broken in 421While nominally embeddable in other event loops, this feature is broken in
407all kernel versions tested so far. 422all kernel versions tested so far.
408 423
409This backend maps C<EV_READ> and C<EV_WRITE> in the same way as 424This backend maps C<EV_READ> and C<EV_WRITE> in the same way as
424 439
425It scales in the same way as the epoll backend, but the interface to the 440It scales in the same way as the epoll backend, but the interface to the
426kernel is more efficient (which says nothing about its actual speed, of 441kernel is more efficient (which says nothing about its actual speed, of
427course). While stopping, setting and starting an I/O watcher does never 442course). While stopping, setting and starting an I/O watcher does never
428cause an extra system call as with C<EVBACKEND_EPOLL>, it still adds up to 443cause an extra system call as with C<EVBACKEND_EPOLL>, it still adds up to
429two event changes per incident. Support for C<fork ()> is very bad and it 444two event changes per incident. Support for C<fork ()> is very bad (but
430drops fds silently in similarly hard-to-detect cases. 445sane, unlike epoll) and it drops fds silently in similarly hard-to-detect
446cases
431 447
432This backend usually performs well under most conditions. 448This backend usually performs well under most conditions.
433 449
434While nominally embeddable in other event loops, this doesn't work 450While nominally embeddable in other event loops, this doesn't work
435everywhere, so you might need to test for this. And since it is broken 451everywhere, so you might need to test for this. And since it is broken
464might perform better. 480might perform better.
465 481
466On the positive side, with the exception of the spurious readiness 482On the positive side, with the exception of the spurious readiness
467notifications, this backend actually performed fully to specification 483notifications, this backend actually performed fully to specification
468in all tests and is fully embeddable, which is a rare feat among the 484in all tests and is fully embeddable, which is a rare feat among the
469OS-specific backends. 485OS-specific backends (I vastly prefer correctness over speed hacks).
470 486
471This backend maps C<EV_READ> and C<EV_WRITE> in the same way as 487This backend maps C<EV_READ> and C<EV_WRITE> in the same way as
472C<EVBACKEND_POLL>. 488C<EVBACKEND_POLL>.
473 489
474=item C<EVBACKEND_ALL> 490=item C<EVBACKEND_ALL>
527responsibility to either stop all watchers cleanly yourself I<before> 543responsibility to either stop all watchers cleanly yourself I<before>
528calling this function, or cope with the fact afterwards (which is usually 544calling this function, or cope with the fact afterwards (which is usually
529the easiest thing, you can just ignore the watchers and/or C<free ()> them 545the easiest thing, you can just ignore the watchers and/or C<free ()> them
530for example). 546for example).
531 547
532Note that certain global state, such as signal state, will not be freed by 548Note that certain global state, such as signal state (and installed signal
533this function, and related watchers (such as signal and child watchers) 549handlers), will not be freed by this function, and related watchers (such
534would need to be stopped manually. 550as signal and child watchers) would need to be stopped manually.
535 551
536In general it is not advisable to call this function except in the 552In general it is not advisable to call this function except in the
537rare occasion where you really need to free e.g. the signal handling 553rare occasion where you really need to free e.g. the signal handling
538pipe fds. If you need dynamically allocated loops it is better to use 554pipe fds. If you need dynamically allocated loops it is better to use
539C<ev_loop_new> and C<ev_loop_destroy>). 555C<ev_loop_new> and C<ev_loop_destroy>).
710respectively). 726respectively).
711 727
712Example: Create a signal watcher, but keep it from keeping C<ev_loop> 728Example: Create a signal watcher, but keep it from keeping C<ev_loop>
713running when nothing else is active. 729running when nothing else is active.
714 730
715 struct ev_signal exitsig; 731 ev_signal exitsig;
716 ev_signal_init (&exitsig, sig_cb, SIGINT); 732 ev_signal_init (&exitsig, sig_cb, SIGINT);
717 ev_signal_start (loop, &exitsig); 733 ev_signal_start (loop, &exitsig);
718 evf_unref (loop); 734 evf_unref (loop);
719 735
720Example: For some weird reason, unregister the above signal handler again. 736Example: For some weird reason, unregister the above signal handler again.
768they fire on, say, one-second boundaries only. 784they fire on, say, one-second boundaries only.
769 785
770=item ev_loop_verify (loop) 786=item ev_loop_verify (loop)
771 787
772This function only does something when C<EV_VERIFY> support has been 788This function only does something when C<EV_VERIFY> support has been
773compiled in. which is the default for non-minimal builds. It tries to go 789compiled in, which is the default for non-minimal builds. It tries to go
774through all internal structures and checks them for validity. If anything 790through all internal structures and checks them for validity. If anything
775is found to be inconsistent, it will print an error message to standard 791is found to be inconsistent, it will print an error message to standard
776error and call C<abort ()>. 792error and call C<abort ()>.
777 793
778This can be used to catch bugs inside libev itself: under normal 794This can be used to catch bugs inside libev itself: under normal
782=back 798=back
783 799
784 800
785=head1 ANATOMY OF A WATCHER 801=head1 ANATOMY OF A WATCHER
786 802
803In the following description, uppercase C<TYPE> in names stands for the
804watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
805watchers and C<ev_io_start> for I/O watchers.
806
787A watcher is a structure that you create and register to record your 807A watcher is a structure that you create and register to record your
788interest in some event. For instance, if you want to wait for STDIN to 808interest in some event. For instance, if you want to wait for STDIN to
789become readable, you would create an C<ev_io> watcher for that: 809become readable, you would create an C<ev_io> watcher for that:
790 810
791 static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) 811 static void my_cb (struct ev_loop *loop, ev_io *w, int revents)
792 { 812 {
793 ev_io_stop (w); 813 ev_io_stop (w);
794 ev_unloop (loop, EVUNLOOP_ALL); 814 ev_unloop (loop, EVUNLOOP_ALL);
795 } 815 }
796 816
797 struct ev_loop *loop = ev_default_loop (0); 817 struct ev_loop *loop = ev_default_loop (0);
818
798 struct ev_io stdin_watcher; 819 ev_io stdin_watcher;
820
799 ev_init (&stdin_watcher, my_cb); 821 ev_init (&stdin_watcher, my_cb);
800 ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ); 822 ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
801 ev_io_start (loop, &stdin_watcher); 823 ev_io_start (loop, &stdin_watcher);
824
802 ev_loop (loop, 0); 825 ev_loop (loop, 0);
803 826
804As you can see, you are responsible for allocating the memory for your 827As you can see, you are responsible for allocating the memory for your
805watcher structures (and it is usually a bad idea to do this on the stack, 828watcher structures (and it is I<usually> a bad idea to do this on the
806although this can sometimes be quite valid). 829stack).
830
831Each watcher has an associated watcher structure (called C<struct ev_TYPE>
832or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
807 833
808Each watcher structure must be initialised by a call to C<ev_init 834Each watcher structure must be initialised by a call to C<ev_init
809(watcher *, callback)>, which expects a callback to be provided. This 835(watcher *, callback)>, which expects a callback to be provided. This
810callback gets invoked each time the event occurs (or, in the case of I/O 836callback gets invoked each time the event occurs (or, in the case of I/O
811watchers, each time the event loop detects that the file descriptor given 837watchers, each time the event loop detects that the file descriptor given
812is readable and/or writable). 838is readable and/or writable).
813 839
814Each watcher type has its own C<< ev_<type>_set (watcher *, ...) >> macro 840Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
815with arguments specific to this watcher type. There is also a macro 841macro to configure it, with arguments specific to the watcher type. There
816to combine initialisation and setting in one call: C<< ev_<type>_init 842is also a macro to combine initialisation and setting in one call: C<<
817(watcher *, callback, ...) >>. 843ev_TYPE_init (watcher *, callback, ...) >>.
818 844
819To make the watcher actually watch out for events, you have to start it 845To make the watcher actually watch out for events, you have to start it
820with a watcher-specific start function (C<< ev_<type>_start (loop, watcher 846with a watcher-specific start function (C<< ev_TYPE_start (loop, watcher
821*) >>), and you can stop watching for events at any time by calling the 847*) >>), and you can stop watching for events at any time by calling the
822corresponding stop function (C<< ev_<type>_stop (loop, watcher *) >>. 848corresponding stop function (C<< ev_TYPE_stop (loop, watcher *) >>.
823 849
824As long as your watcher is active (has been started but not stopped) you 850As long as your watcher is active (has been started but not stopped) you
825must not touch the values stored in it. Most specifically you must never 851must not touch the values stored in it. Most specifically you must never
826reinitialise it or call its C<set> macro. 852reinitialise it or call its C<ev_TYPE_set> macro.
827 853
828Each and every callback receives the event loop pointer as first, the 854Each and every callback receives the event loop pointer as first, the
829registered watcher structure as second, and a bitset of received events as 855registered watcher structure as second, and a bitset of received events as
830third argument. 856third argument.
831 857
894=item C<EV_ERROR> 920=item C<EV_ERROR>
895 921
896An unspecified error has occurred, the watcher has been stopped. This might 922An unspecified error has occurred, the watcher has been stopped. This might
897happen because the watcher could not be properly started because libev 923happen because the watcher could not be properly started because libev
898ran out of memory, a file descriptor was found to be closed or any other 924ran out of memory, a file descriptor was found to be closed or any other
925problem. Libev considers these application bugs.
926
899problem. You best act on it by reporting the problem and somehow coping 927You best act on it by reporting the problem and somehow coping with the
900with the watcher being stopped. 928watcher being stopped. Note that well-written programs should not receive
929an error ever, so when your watcher receives it, this usually indicates a
930bug in your program.
901 931
902Libev will usually signal a few "dummy" events together with an error, for 932Libev will usually signal a few "dummy" events together with an error, for
903example it might indicate that a fd is readable or writable, and if your 933example it might indicate that a fd is readable or writable, and if your
904callbacks is well-written it can just attempt the operation and cope with 934callbacks is well-written it can just attempt the operation and cope with
905the error from read() or write(). This will not work in multi-threaded 935the error from read() or write(). This will not work in multi-threaded
908 938
909=back 939=back
910 940
911=head2 GENERIC WATCHER FUNCTIONS 941=head2 GENERIC WATCHER FUNCTIONS
912 942
913In the following description, C<TYPE> stands for the watcher type,
914e.g. C<timer> for C<ev_timer> watchers and C<io> for C<ev_io> watchers.
915
916=over 4 943=over 4
917 944
918=item C<ev_init> (ev_TYPE *watcher, callback) 945=item C<ev_init> (ev_TYPE *watcher, callback)
919 946
920This macro initialises the generic portion of a watcher. The contents 947This macro initialises the generic portion of a watcher. The contents
925which rolls both calls into one. 952which rolls both calls into one.
926 953
927You can reinitialise a watcher at any time as long as it has been stopped 954You can reinitialise a watcher at any time as long as it has been stopped
928(or never started) and there are no pending events outstanding. 955(or never started) and there are no pending events outstanding.
929 956
930The callback is always of type C<void (*)(ev_loop *loop, ev_TYPE *watcher, 957The callback is always of type C<void (*)(struct ev_loop *loop, ev_TYPE *watcher,
931int revents)>. 958int revents)>.
932 959
933Example: Initialise an C<ev_io> watcher in two steps. 960Example: Initialise an C<ev_io> watcher in two steps.
934 961
935 ev_io w; 962 ev_io w;
1028The default priority used by watchers when no priority has been set is 1055The default priority used by watchers when no priority has been set is
1029always C<0>, which is supposed to not be too high and not be too low :). 1056always C<0>, which is supposed to not be too high and not be too low :).
1030 1057
1031Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is 1058Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is
1032fine, as long as you do not mind that the priority value you query might 1059fine, as long as you do not mind that the priority value you query might
1033or might not have been adjusted to be within valid range. 1060or might not have been clamped to the valid range.
1034 1061
1035=item ev_invoke (loop, ev_TYPE *watcher, int revents) 1062=item ev_invoke (loop, ev_TYPE *watcher, int revents)
1036 1063
1037Invoke the C<watcher> with the given C<loop> and C<revents>. Neither 1064Invoke the C<watcher> with the given C<loop> and C<revents>. Neither
1038C<loop> nor C<revents> need to be valid as long as the watcher callback 1065C<loop> nor C<revents> need to be valid as long as the watcher callback
1060member, you can also "subclass" the watcher type and provide your own 1087member, you can also "subclass" the watcher type and provide your own
1061data: 1088data:
1062 1089
1063 struct my_io 1090 struct my_io
1064 { 1091 {
1065 struct ev_io io; 1092 ev_io io;
1066 int otherfd; 1093 int otherfd;
1067 void *somedata; 1094 void *somedata;
1068 struct whatever *mostinteresting; 1095 struct whatever *mostinteresting;
1069 }; 1096 };
1070 1097
1073 ev_io_init (&w.io, my_cb, fd, EV_READ); 1100 ev_io_init (&w.io, my_cb, fd, EV_READ);
1074 1101
1075And since your callback will be called with a pointer to the watcher, you 1102And since your callback will be called with a pointer to the watcher, you
1076can cast it back to your own type: 1103can cast it back to your own type:
1077 1104
1078 static void my_cb (struct ev_loop *loop, struct ev_io *w_, int revents) 1105 static void my_cb (struct ev_loop *loop, ev_io *w_, int revents)
1079 { 1106 {
1080 struct my_io *w = (struct my_io *)w_; 1107 struct my_io *w = (struct my_io *)w_;
1081 ... 1108 ...
1082 } 1109 }
1083 1110
1101programmers): 1128programmers):
1102 1129
1103 #include <stddef.h> 1130 #include <stddef.h>
1104 1131
1105 static void 1132 static void
1106 t1_cb (EV_P_ struct ev_timer *w, int revents) 1133 t1_cb (EV_P_ ev_timer *w, int revents)
1107 { 1134 {
1108 struct my_biggy big = (struct my_biggy * 1135 struct my_biggy big = (struct my_biggy *
1109 (((char *)w) - offsetof (struct my_biggy, t1)); 1136 (((char *)w) - offsetof (struct my_biggy, t1));
1110 } 1137 }
1111 1138
1112 static void 1139 static void
1113 t2_cb (EV_P_ struct ev_timer *w, int revents) 1140 t2_cb (EV_P_ ev_timer *w, int revents)
1114 { 1141 {
1115 struct my_biggy big = (struct my_biggy * 1142 struct my_biggy big = (struct my_biggy *
1116 (((char *)w) - offsetof (struct my_biggy, t2)); 1143 (((char *)w) - offsetof (struct my_biggy, t2));
1117 } 1144 }
1118 1145
1253Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well 1280Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well
1254readable, but only once. Since it is likely line-buffered, you could 1281readable, but only once. Since it is likely line-buffered, you could
1255attempt to read a whole line in the callback. 1282attempt to read a whole line in the callback.
1256 1283
1257 static void 1284 static void
1258 stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) 1285 stdin_readable_cb (struct ev_loop *loop, ev_io *w, int revents)
1259 { 1286 {
1260 ev_io_stop (loop, w); 1287 ev_io_stop (loop, w);
1261 .. read from stdin here (or from w->fd) and handle any I/O errors 1288 .. read from stdin here (or from w->fd) and handle any I/O errors
1262 } 1289 }
1263 1290
1264 ... 1291 ...
1265 struct ev_loop *loop = ev_default_init (0); 1292 struct ev_loop *loop = ev_default_init (0);
1266 struct ev_io stdin_readable; 1293 ev_io stdin_readable;
1267 ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); 1294 ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1268 ev_io_start (loop, &stdin_readable); 1295 ev_io_start (loop, &stdin_readable);
1269 ev_loop (loop, 0); 1296 ev_loop (loop, 0);
1270 1297
1271 1298
1282 1309
1283The callback is guaranteed to be invoked only I<after> its timeout has 1310The callback is guaranteed to be invoked only I<after> its timeout has
1284passed, but if multiple timers become ready during the same loop iteration 1311passed, but if multiple timers become ready during the same loop iteration
1285then order of execution is undefined. 1312then order of execution is undefined.
1286 1313
1314=head3 Be smart about timeouts
1315
1316Many real-world problems involve some kind of timeout, usually for error
1317recovery. A typical example is an HTTP request - if the other side hangs,
1318you want to raise some error after a while.
1319
1320What follows are some ways to handle this problem, from obvious and
1321inefficient to smart and efficient.
1322
1323In the following, a 60 second activity timeout is assumed - a timeout that
1324gets reset to 60 seconds each time there is activity (e.g. each time some
1325data or other life sign was received).
1326
1327=over 4
1328
1329=item 1. Use a timer and stop, reinitialise and start it on activity.
1330
1331This is the most obvious, but not the most simple way: In the beginning,
1332start the watcher:
1333
1334 ev_timer_init (timer, callback, 60., 0.);
1335 ev_timer_start (loop, timer);
1336
1337Then, each time there is some activity, C<ev_timer_stop> it, initialise it
1338and start it again:
1339
1340 ev_timer_stop (loop, timer);
1341 ev_timer_set (timer, 60., 0.);
1342 ev_timer_start (loop, timer);
1343
1344This is relatively simple to implement, but means that each time there is
1345some activity, libev will first have to remove the timer from its internal
1346data structure and then add it again. Libev tries to be fast, but it's
1347still not a constant-time operation.
1348
1349=item 2. Use a timer and re-start it with C<ev_timer_again> inactivity.
1350
1351This is the easiest way, and involves using C<ev_timer_again> instead of
1352C<ev_timer_start>.
1353
1354To implement this, configure an C<ev_timer> with a C<repeat> value
1355of C<60> and then call C<ev_timer_again> at start and each time you
1356successfully read or write some data. If you go into an idle state where
1357you do not expect data to travel on the socket, you can C<ev_timer_stop>
1358the timer, and C<ev_timer_again> will automatically restart it if need be.
1359
1360That means you can ignore both the C<ev_timer_start> function and the
1361C<after> argument to C<ev_timer_set>, and only ever use the C<repeat>
1362member and C<ev_timer_again>.
1363
1364At start:
1365
1366 ev_timer_init (timer, callback);
1367 timer->repeat = 60.;
1368 ev_timer_again (loop, timer);
1369
1370Each time there is some activity:
1371
1372 ev_timer_again (loop, timer);
1373
1374It is even possible to change the time-out on the fly, regardless of
1375whether the watcher is active or not:
1376
1377 timer->repeat = 30.;
1378 ev_timer_again (loop, timer);
1379
1380This is slightly more efficient then stopping/starting the timer each time
1381you want to modify its timeout value, as libev does not have to completely
1382remove and re-insert the timer from/into its internal data structure.
1383
1384It is, however, even simpler than the "obvious" way to do it.
1385
1386=item 3. Let the timer time out, but then re-arm it as required.
1387
1388This method is more tricky, but usually most efficient: Most timeouts are
1389relatively long compared to the intervals between other activity - in
1390our example, within 60 seconds, there are usually many I/O events with
1391associated activity resets.
1392
1393In this case, it would be more efficient to leave the C<ev_timer> alone,
1394but remember the time of last activity, and check for a real timeout only
1395within the callback:
1396
1397 ev_tstamp last_activity; // time of last activity
1398
1399 static void
1400 callback (EV_P_ ev_timer *w, int revents)
1401 {
1402 ev_tstamp now = ev_now (EV_A);
1403 ev_tstamp timeout = last_activity + 60.;
1404
1405 // if last_activity + 60. is older than now, we did time out
1406 if (timeout < now)
1407 {
1408 // timeout occured, take action
1409 }
1410 else
1411 {
1412 // callback was invoked, but there was some activity, re-arm
1413 // the watcher to fire in last_activity + 60, which is
1414 // guaranteed to be in the future, so "again" is positive:
1415 w->again = timeout - now;
1416 ev_timer_again (EV_A_ w);
1417 }
1418 }
1419
1420To summarise the callback: first calculate the real timeout (defined
1421as "60 seconds after the last activity"), then check if that time has
1422been reached, which means something I<did>, in fact, time out. Otherwise
1423the callback was invoked too early (C<timeout> is in the future), so
1424re-schedule the timer to fire at that future time, to see if maybe we have
1425a timeout then.
1426
1427Note how C<ev_timer_again> is used, taking advantage of the
1428C<ev_timer_again> optimisation when the timer is already running.
1429
1430This scheme causes more callback invocations (about one every 60 seconds
1431minus half the average time between activity), but virtually no calls to
1432libev to change the timeout.
1433
1434To start the timer, simply initialise the watcher and set C<last_activity>
1435to the current time (meaning we just have some activity :), then call the
1436callback, which will "do the right thing" and start the timer:
1437
1438 ev_timer_init (timer, callback);
1439 last_activity = ev_now (loop);
1440 callback (loop, timer, EV_TIMEOUT);
1441
1442And when there is some activity, simply store the current time in
1443C<last_activity>, no libev calls at all:
1444
1445 last_actiivty = ev_now (loop);
1446
1447This technique is slightly more complex, but in most cases where the
1448time-out is unlikely to be triggered, much more efficient.
1449
1450Changing the timeout is trivial as well (if it isn't hard-coded in the
1451callback :) - just change the timeout and invoke the callback, which will
1452fix things for you.
1453
1454=item 4. Wee, just use a double-linked list for your timeouts.
1455
1456If there is not one request, but many thousands (millions...), all
1457employing some kind of timeout with the same timeout value, then one can
1458do even better:
1459
1460When starting the timeout, calculate the timeout value and put the timeout
1461at the I<end> of the list.
1462
1463Then use an C<ev_timer> to fire when the timeout at the I<beginning> of
1464the list is expected to fire (for example, using the technique #3).
1465
1466When there is some activity, remove the timer from the list, recalculate
1467the timeout, append it to the end of the list again, and make sure to
1468update the C<ev_timer> if it was taken from the beginning of the list.
1469
1470This way, one can manage an unlimited number of timeouts in O(1) time for
1471starting, stopping and updating the timers, at the expense of a major
1472complication, and having to use a constant timeout. The constant timeout
1473ensures that the list stays sorted.
1474
1475=back
1476
1477So which method the best?
1478
1479Method #2 is a simple no-brain-required solution that is adequate in most
1480situations. Method #3 requires a bit more thinking, but handles many cases
1481better, and isn't very complicated either. In most case, choosing either
1482one is fine, with #3 being better in typical situations.
1483
1484Method #1 is almost always a bad idea, and buys you nothing. Method #4 is
1485rather complicated, but extremely efficient, something that really pays
1486off after the first million or so of active timers, i.e. it's usually
1487overkill :)
1488
1287=head3 The special problem of time updates 1489=head3 The special problem of time updates
1288 1490
1289Establishing the current time is a costly operation (it usually takes at 1491Establishing the current time is a costly operation (it usually takes at
1290least two system calls): EV therefore updates its idea of the current 1492least two system calls): EV therefore updates its idea of the current
1291time only before and after C<ev_loop> collects new events, which causes a 1493time only before and after C<ev_loop> collects new events, which causes a
1334If the timer is started but non-repeating, stop it (as if it timed out). 1536If the timer is started but non-repeating, stop it (as if it timed out).
1335 1537
1336If the timer is repeating, either start it if necessary (with the 1538If the timer is repeating, either start it if necessary (with the
1337C<repeat> value), or reset the running timer to the C<repeat> value. 1539C<repeat> value), or reset the running timer to the C<repeat> value.
1338 1540
1339This sounds a bit complicated, but here is a useful and typical 1541This sounds a bit complicated, see "Be smart about timeouts", above, for a
1340example: Imagine you have a TCP connection and you want a so-called idle 1542usage example.
1341timeout, that is, you want to be called when there have been, say, 60
1342seconds of inactivity on the socket. The easiest way to do this is to
1343configure an C<ev_timer> with a C<repeat> value of C<60> and then call
1344C<ev_timer_again> each time you successfully read or write some data. If
1345you go into an idle state where you do not expect data to travel on the
1346socket, you can C<ev_timer_stop> the timer, and C<ev_timer_again> will
1347automatically restart it if need be.
1348
1349That means you can ignore the C<after> value and C<ev_timer_start>
1350altogether and only ever use the C<repeat> value and C<ev_timer_again>:
1351
1352 ev_timer_init (timer, callback, 0., 5.);
1353 ev_timer_again (loop, timer);
1354 ...
1355 timer->again = 17.;
1356 ev_timer_again (loop, timer);
1357 ...
1358 timer->again = 10.;
1359 ev_timer_again (loop, timer);
1360
1361This is more slightly efficient then stopping/starting the timer each time
1362you want to modify its timeout value.
1363
1364Note, however, that it is often even more efficient to remember the
1365time of the last activity and let the timer time-out naturally. In the
1366callback, you then check whether the time-out is real, or, if there was
1367some activity, you reschedule the watcher to time-out in "last_activity +
1368timeout - ev_now ()" seconds.
1369 1543
1370=item ev_tstamp repeat [read-write] 1544=item ev_tstamp repeat [read-write]
1371 1545
1372The current C<repeat> value. Will be used each time the watcher times out 1546The current C<repeat> value. Will be used each time the watcher times out
1373or C<ev_timer_again> is called, and determines the next timeout (if any), 1547or C<ev_timer_again> is called, and determines the next timeout (if any),
1378=head3 Examples 1552=head3 Examples
1379 1553
1380Example: Create a timer that fires after 60 seconds. 1554Example: Create a timer that fires after 60 seconds.
1381 1555
1382 static void 1556 static void
1383 one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) 1557 one_minute_cb (struct ev_loop *loop, ev_timer *w, int revents)
1384 { 1558 {
1385 .. one minute over, w is actually stopped right here 1559 .. one minute over, w is actually stopped right here
1386 } 1560 }
1387 1561
1388 struct ev_timer mytimer; 1562 ev_timer mytimer;
1389 ev_timer_init (&mytimer, one_minute_cb, 60., 0.); 1563 ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
1390 ev_timer_start (loop, &mytimer); 1564 ev_timer_start (loop, &mytimer);
1391 1565
1392Example: Create a timeout timer that times out after 10 seconds of 1566Example: Create a timeout timer that times out after 10 seconds of
1393inactivity. 1567inactivity.
1394 1568
1395 static void 1569 static void
1396 timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) 1570 timeout_cb (struct ev_loop *loop, ev_timer *w, int revents)
1397 { 1571 {
1398 .. ten seconds without any activity 1572 .. ten seconds without any activity
1399 } 1573 }
1400 1574
1401 struct ev_timer mytimer; 1575 ev_timer mytimer;
1402 ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ 1576 ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1403 ev_timer_again (&mytimer); /* start timer */ 1577 ev_timer_again (&mytimer); /* start timer */
1404 ev_loop (loop, 0); 1578 ev_loop (loop, 0);
1405 1579
1406 // and in some piece of code that gets executed on any "activity": 1580 // and in some piece of code that gets executed on any "activity":
1492 1666
1493If you need to stop it, return C<now + 1e30> (or so, fudge fudge) and stop 1667If you need to stop it, return C<now + 1e30> (or so, fudge fudge) and stop
1494it afterwards (e.g. by starting an C<ev_prepare> watcher, which is the 1668it afterwards (e.g. by starting an C<ev_prepare> watcher, which is the
1495only event loop modification you are allowed to do). 1669only event loop modification you are allowed to do).
1496 1670
1497The callback prototype is C<ev_tstamp (*reschedule_cb)(struct ev_periodic 1671The callback prototype is C<ev_tstamp (*reschedule_cb)(ev_periodic
1498*w, ev_tstamp now)>, e.g.: 1672*w, ev_tstamp now)>, e.g.:
1499 1673
1674 static ev_tstamp
1500 static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now) 1675 my_rescheduler (ev_periodic *w, ev_tstamp now)
1501 { 1676 {
1502 return now + 60.; 1677 return now + 60.;
1503 } 1678 }
1504 1679
1505It must return the next time to trigger, based on the passed time value 1680It must return the next time to trigger, based on the passed time value
1542 1717
1543The current interval value. Can be modified any time, but changes only 1718The current interval value. Can be modified any time, but changes only
1544take effect when the periodic timer fires or C<ev_periodic_again> is being 1719take effect when the periodic timer fires or C<ev_periodic_again> is being
1545called. 1720called.
1546 1721
1547=item ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write] 1722=item ev_tstamp (*reschedule_cb)(ev_periodic *w, ev_tstamp now) [read-write]
1548 1723
1549The current reschedule callback, or C<0>, if this functionality is 1724The current reschedule callback, or C<0>, if this functionality is
1550switched off. Can be changed any time, but changes only take effect when 1725switched off. Can be changed any time, but changes only take effect when
1551the periodic timer fires or C<ev_periodic_again> is being called. 1726the periodic timer fires or C<ev_periodic_again> is being called.
1552 1727
1557Example: Call a callback every hour, or, more precisely, whenever the 1732Example: Call a callback every hour, or, more precisely, whenever the
1558system time is divisible by 3600. The callback invocation times have 1733system time is divisible by 3600. The callback invocation times have
1559potentially a lot of jitter, but good long-term stability. 1734potentially a lot of jitter, but good long-term stability.
1560 1735
1561 static void 1736 static void
1562 clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) 1737 clock_cb (struct ev_loop *loop, ev_io *w, int revents)
1563 { 1738 {
1564 ... its now a full hour (UTC, or TAI or whatever your clock follows) 1739 ... its now a full hour (UTC, or TAI or whatever your clock follows)
1565 } 1740 }
1566 1741
1567 struct ev_periodic hourly_tick; 1742 ev_periodic hourly_tick;
1568 ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); 1743 ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
1569 ev_periodic_start (loop, &hourly_tick); 1744 ev_periodic_start (loop, &hourly_tick);
1570 1745
1571Example: The same as above, but use a reschedule callback to do it: 1746Example: The same as above, but use a reschedule callback to do it:
1572 1747
1573 #include <math.h> 1748 #include <math.h>
1574 1749
1575 static ev_tstamp 1750 static ev_tstamp
1576 my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) 1751 my_scheduler_cb (ev_periodic *w, ev_tstamp now)
1577 { 1752 {
1578 return now + (3600. - fmod (now, 3600.)); 1753 return now + (3600. - fmod (now, 3600.));
1579 } 1754 }
1580 1755
1581 ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); 1756 ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
1582 1757
1583Example: Call a callback every hour, starting now: 1758Example: Call a callback every hour, starting now:
1584 1759
1585 struct ev_periodic hourly_tick; 1760 ev_periodic hourly_tick;
1586 ev_periodic_init (&hourly_tick, clock_cb, 1761 ev_periodic_init (&hourly_tick, clock_cb,
1587 fmod (ev_now (loop), 3600.), 3600., 0); 1762 fmod (ev_now (loop), 3600.), 3600., 0);
1588 ev_periodic_start (loop, &hourly_tick); 1763 ev_periodic_start (loop, &hourly_tick);
1589 1764
1590 1765
1632=head3 Examples 1807=head3 Examples
1633 1808
1634Example: Try to exit cleanly on SIGINT. 1809Example: Try to exit cleanly on SIGINT.
1635 1810
1636 static void 1811 static void
1637 sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) 1812 sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)
1638 { 1813 {
1639 ev_unloop (loop, EVUNLOOP_ALL); 1814 ev_unloop (loop, EVUNLOOP_ALL);
1640 } 1815 }
1641 1816
1642 struct ev_signal signal_watcher; 1817 ev_signal signal_watcher;
1643 ev_signal_init (&signal_watcher, sigint_cb, SIGINT); 1818 ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
1644 ev_signal_start (loop, &signal_watcher); 1819 ev_signal_start (loop, &signal_watcher);
1645 1820
1646 1821
1647=head2 C<ev_child> - watch out for process status changes 1822=head2 C<ev_child> - watch out for process status changes
1722its completion. 1897its completion.
1723 1898
1724 ev_child cw; 1899 ev_child cw;
1725 1900
1726 static void 1901 static void
1727 child_cb (EV_P_ struct ev_child *w, int revents) 1902 child_cb (EV_P_ ev_child *w, int revents)
1728 { 1903 {
1729 ev_child_stop (EV_A_ w); 1904 ev_child_stop (EV_A_ w);
1730 printf ("process %d exited with status %x\n", w->rpid, w->rstatus); 1905 printf ("process %d exited with status %x\n", w->rpid, w->rstatus);
1731 } 1906 }
1732 1907
1796to exchange stat structures with application programs compiled using the 1971to exchange stat structures with application programs compiled using the
1797default compilation environment. 1972default compilation environment.
1798 1973
1799=head3 Inotify and Kqueue 1974=head3 Inotify and Kqueue
1800 1975
1801When C<inotify (7)> support has been compiled into libev (generally only 1976When C<inotify (7)> support has been compiled into libev (generally
1977only available with Linux 2.6.25 or above due to bugs in earlier
1802available with Linux) and present at runtime, it will be used to speed up 1978implementations) and present at runtime, it will be used to speed up
1803change detection where possible. The inotify descriptor will be created lazily 1979change detection where possible. The inotify descriptor will be created
1804when the first C<ev_stat> watcher is being started. 1980lazily when the first C<ev_stat> watcher is being started.
1805 1981
1806Inotify presence does not change the semantics of C<ev_stat> watchers 1982Inotify presence does not change the semantics of C<ev_stat> watchers
1807except that changes might be detected earlier, and in some cases, to avoid 1983except that changes might be detected earlier, and in some cases, to avoid
1808making regular C<stat> calls. Even in the presence of inotify support 1984making regular C<stat> calls. Even in the presence of inotify support
1809there are many cases where libev has to resort to regular C<stat> polling, 1985there are many cases where libev has to resort to regular C<stat> polling,
1983 2159
1984Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the 2160Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the
1985callback, free it. Also, use no error checking, as usual. 2161callback, free it. Also, use no error checking, as usual.
1986 2162
1987 static void 2163 static void
1988 idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) 2164 idle_cb (struct ev_loop *loop, ev_idle *w, int revents)
1989 { 2165 {
1990 free (w); 2166 free (w);
1991 // now do something you wanted to do when the program has 2167 // now do something you wanted to do when the program has
1992 // no longer anything immediate to do. 2168 // no longer anything immediate to do.
1993 } 2169 }
1994 2170
1995 struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); 2171 ev_idle *idle_watcher = malloc (sizeof (ev_idle));
1996 ev_idle_init (idle_watcher, idle_cb); 2172 ev_idle_init (idle_watcher, idle_cb);
1997 ev_idle_start (loop, idle_cb); 2173 ev_idle_start (loop, idle_cb);
1998 2174
1999 2175
2000=head2 C<ev_prepare> and C<ev_check> - customise your event loop! 2176=head2 C<ev_prepare> and C<ev_check> - customise your event loop!
2081 2257
2082 static ev_io iow [nfd]; 2258 static ev_io iow [nfd];
2083 static ev_timer tw; 2259 static ev_timer tw;
2084 2260
2085 static void 2261 static void
2086 io_cb (ev_loop *loop, ev_io *w, int revents) 2262 io_cb (struct ev_loop *loop, ev_io *w, int revents)
2087 { 2263 {
2088 } 2264 }
2089 2265
2090 // create io watchers for each fd and a timer before blocking 2266 // create io watchers for each fd and a timer before blocking
2091 static void 2267 static void
2092 adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) 2268 adns_prepare_cb (struct ev_loop *loop, ev_prepare *w, int revents)
2093 { 2269 {
2094 int timeout = 3600000; 2270 int timeout = 3600000;
2095 struct pollfd fds [nfd]; 2271 struct pollfd fds [nfd];
2096 // actual code will need to loop here and realloc etc. 2272 // actual code will need to loop here and realloc etc.
2097 adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); 2273 adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
2112 } 2288 }
2113 } 2289 }
2114 2290
2115 // stop all watchers after blocking 2291 // stop all watchers after blocking
2116 static void 2292 static void
2117 adns_check_cb (ev_loop *loop, ev_check *w, int revents) 2293 adns_check_cb (struct ev_loop *loop, ev_check *w, int revents)
2118 { 2294 {
2119 ev_timer_stop (loop, &tw); 2295 ev_timer_stop (loop, &tw);
2120 2296
2121 for (int i = 0; i < nfd; ++i) 2297 for (int i = 0; i < nfd; ++i)
2122 { 2298 {
2290C<loop_lo> (which is C<loop_hi> in the case no embeddable loop can be 2466C<loop_lo> (which is C<loop_hi> in the case no embeddable loop can be
2291used). 2467used).
2292 2468
2293 struct ev_loop *loop_hi = ev_default_init (0); 2469 struct ev_loop *loop_hi = ev_default_init (0);
2294 struct ev_loop *loop_lo = 0; 2470 struct ev_loop *loop_lo = 0;
2295 struct ev_embed embed; 2471 ev_embed embed;
2296 2472
2297 // see if there is a chance of getting one that works 2473 // see if there is a chance of getting one that works
2298 // (remember that a flags value of 0 means autodetection) 2474 // (remember that a flags value of 0 means autodetection)
2299 loop_lo = ev_embeddable_backends () & ev_recommended_backends () 2475 loop_lo = ev_embeddable_backends () & ev_recommended_backends ()
2300 ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) 2476 ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ())
2314kqueue implementation). Store the kqueue/socket-only event loop in 2490kqueue implementation). Store the kqueue/socket-only event loop in
2315C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too). 2491C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too).
2316 2492
2317 struct ev_loop *loop = ev_default_init (0); 2493 struct ev_loop *loop = ev_default_init (0);
2318 struct ev_loop *loop_socket = 0; 2494 struct ev_loop *loop_socket = 0;
2319 struct ev_embed embed; 2495 ev_embed embed;
2320 2496
2321 if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE) 2497 if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE)
2322 if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE)) 2498 if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE))
2323 { 2499 {
2324 ev_embed_init (&embed, 0, loop_socket); 2500 ev_embed_init (&embed, 0, loop_socket);
2538 /* doh, nothing entered */; 2714 /* doh, nothing entered */;
2539 } 2715 }
2540 2716
2541 ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); 2717 ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
2542 2718
2543=item ev_feed_event (ev_loop *, watcher *, int revents) 2719=item ev_feed_event (struct ev_loop *, watcher *, int revents)
2544 2720
2545Feeds the given event set into the event loop, as if the specified event 2721Feeds the given event set into the event loop, as if the specified event
2546had happened for the specified watcher (which must be a pointer to an 2722had happened for the specified watcher (which must be a pointer to an
2547initialised but not necessarily started event watcher). 2723initialised but not necessarily started event watcher).
2548 2724
2549=item ev_feed_fd_event (ev_loop *, int fd, int revents) 2725=item ev_feed_fd_event (struct ev_loop *, int fd, int revents)
2550 2726
2551Feed an event on the given fd, as if a file descriptor backend detected 2727Feed an event on the given fd, as if a file descriptor backend detected
2552the given events it. 2728the given events it.
2553 2729
2554=item ev_feed_signal_event (ev_loop *loop, int signum) 2730=item ev_feed_signal_event (struct ev_loop *loop, int signum)
2555 2731
2556Feed an event as if the given signal occurred (C<loop> must be the default 2732Feed an event as if the given signal occurred (C<loop> must be the default
2557loop!). 2733loop!).
2558 2734
2559=back 2735=back
2793 2969
2794=item D 2970=item D
2795 2971
2796Leandro Lucarella has written a D language binding (F<ev.d>) for libev, to 2972Leandro Lucarella has written a D language binding (F<ev.d>) for libev, to
2797be found at L<http://proj.llucax.com.ar/wiki/evd>. 2973be found at L<http://proj.llucax.com.ar/wiki/evd>.
2974
2975=item Ocaml
2976
2977Erkki Seppala has written Ocaml bindings for libev, to be found at
2978L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>.
2798 2979
2799=back 2980=back
2800 2981
2801 2982
2802=head1 MACRO MAGIC 2983=head1 MACRO MAGIC

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